In open cockpit vehicles, such as motorcycles, a fairing or windshield of curved clear plastic is typically provided to protect the rider from the effects of wind and particulate or rain in the air.
As motorcycles have been modernized and streamlined, the windshield mounted on the vehicles have gradually decreased in length and taken on a much steeper angle (oriented more towards the horizontal). While these modifications decrease wind resistance, they require that the rider lean downwardly closely adjacent the vehicle so as to take advantage of the slip stream created by the steeply sloped windshield.
For the taller rider, or the rider who does not wish to lean forwardly and downwardly, the air passing over the windshield will contact the face or helmet of the rider, causing vibration in the motorcyclist's helmet and a buffeting air pattern around the head of the rider, within the cockpit of the motorcycle.